Method of and apparatus for die casting



Dec. 2s, 1926.

J. L. JONES METHOD 0F AND APPARATUS FOR DIE CASTING Filed Nov. 20,

f i Y /O 7 .1 1./ \7

. INVI- NTOR ATTORNEY Patented Dec. 28, 1926.

UNITED STATES JESSE L. JONES, OF EDGEWOOD, PENNSYLVANIA,

TRIC &` MANUFACTURING COMPANY,

ASSIGNOR T WESTINGHOUSE ELEC-y A CORPORATION 0F PENNSYLVANIA.

METHOD 0F AND APPARATUS FOR DIE CASTING.

Application 4filed November 20, 1923. Serial No. 675,831.

My invention relates'to pressure casting, more especially to an apparatus for casting metal bodies, such as squirrel cage rotors for dynan'lo-electric machines in dies or molds under relatively high pressures.

Alt is among the objects of my invention lo provide a device for casting metal bodies under pressure which shall be ofsimple, durable, mechanical construction and which shall be clicient in the casting of rotors or the like with uniform results and in production quantities.

Pressure casting methods as ordinarily practiced, utilize a die or mold of the shape and contour of the body to be formed, the molds being sometimes adapted to hold a structure which becomes a part ofthe casting formed therein. The die or mold is provided with a reservoir which contains a molten metal, such as aluminum, cooper or the like, which is forced through one or more communicating ports into the matrix of the mold under relatively high pressures.

The cooling of the metal in the mold results in irregularities due to shrinkage anl blow-holes, if thepressures utilized are insufficient to counteract the stresses set up in cooling.

I propose to overcome these irregularities in the casting 1by filling the mold from two or more sources so that the metal forced into the mold fromone sidewill be compressed by the metal subsequently forced from the opposite side a short time later.

In the accompanying drawing constituting a part hereof and in which like reference characters designate like parts, the single figure is a vertical sectional view of a pressure casting device embodying the principles of my invention. f

The device comprises a die or mold 1, consisting of a cylindrical shell 2 having an otfl-set portion 3 and which is mounted on a base 4 in a suitable vmanner, as by means of a connecting flange 5 which constitutes the base plate of the mold. A cylindrical member` 6 is mounted on the top of the mold 1 by a flanged plate 7 which constitutes the clamping member of mold 1. The members 4 and 6 are'provided with cylindrical openings 8 having pistons -9 and 10, respectively, movably mounted therein.

The openings 8 constitute, reservoirs in which the` molten metal, such. as aluminum, copper or the like, is stored and the pistous 9 and 10 are connected up in a suitable manner to be successively operated by i'nechanical levers or by the usual pressureactuated devices.

A rotor 12 comprising a plurality of super-posed steel laminations having a central opening 13 and a pluralityv of slots or openings 14, which receive the metal to constitute the rotor bars when the casting is completed, is assembled between the base plate 5 and-the clamping plate 7. The plates 5 und 7 are so formed as to provide annular recesses 15 at the ends of the members 12, the metal within which constitutes the end rings of the rotor when cast. The end rings are formed integral with the metal conductors in the slots 14. The mold 1 is provided with av plurality of port-holes 16 which are closed by asbestos,cloth or the like to prevent the molten metal 11 from the iowling into the moldprematurely,

before the piston members are actuated.

When the laminated rotor 12 is assembled between the plates of the mold as shown,

d the bottom piston 9 is actuated to force thev moltenmetal from the lower reservoir into the spaces 14 and 15 and form the lower end ring and a portion ofthe conductor bars, the amount of metal in the reservoir beinglimited so as to .only partially form the casting. forming of the`lower body portion of the casting, the upper piston member 10 is actuated against the metal in the upper reservoir which is forced into the mold under extremely high pressure, 'before the metal discharged from the lower reservoir is completely set or hardened, thus tending to counteract the effective shrinkage in the bottom-casting to prevent' the shrinkage of the metal and the formation of blow-ho1es. The mold 1v is then removed by actuating it about the pivot pins 17 and the casting is discharged by removing the upper clamping plate 7 which gives access to the casting and the latter is readily removed by unscrewing the clamping bolt 18 and raising the casting out of. the matrix 2. A new rotor is then inserted and the operation repeated.

A short interval aftery the' It is evident .from the abbve description of my invention that a pressure casting device as set forth herein provides an efficient means for forming pressure cast bodies of homogeneous structure and with uniform re- 'from the second ond reservoir,

sure which comprises formin sults and especially bodies of metal .having relativel age resu ting from'theL cooling of the metal is counteracted by the subsequent supply source. My device is especially adapted for casting end rings and conductor bars on squirrel cage rotors for dynamo electric machines as these members are of irregular' cross-'scctiom which offers a relatively large cooling surface for the metal.

Although I have described a specific ernbodiment of my invention, it Will be ob-l vious to those skilled in the art that the general design features may be varied in proportions and mechanical fittings to adapt them for the casting of'various sized rotors and bodies of other shapes than herein illustrated without departing from the spirit of my invention.

I claim as my invention z- 1. A method of casting bodies under pressurc which comprises forming "such bodies by casting molten metal under pressure. from a plurality of independent sources successively into a single mold.

2. A method of casting bodies under pressure Which comprises forming such bodies by casting a portion of the body froma reservoir containing a limited amount of metal and completing the body from a secthe metal being forced into themold under pressure from both reservoirs.

3. A method of casting bodiesunder pressuch bodies by casting a portion of the bo y under pressure from a reservoir containing a limited amount of metal and com leting the body with molten metal cast undldr pressure from another reservoir after the first named reservoir has been discharged.

4. A method of casting bodies under pressure which comprises forming such bodies by casting a portion of the body under pressure from a reservoir containing a limited high shrinkage, as the shrinky-` .amount of metal and completing the body with molten metal cast under ressu're from another reservoir at a slight interval after the first reservoir is discharged.

5. A pressure casting ldevice comprising a mold, a plurality of reservoirs for holding a supply of molten metal, communicating means for said mold and reservoirs and cmeans for discharging said reservoirs at successive intervals.

- 6. A pressure casting device comprising a mold, a plurallty of reservoirs Alor holding a supply of molten metal, communicating reservoirs associated with said mold, a plurality of communicating ports in said mold and reservoirs and pressure actuating means llor discharging .the reservoirs through said ports. A

8. A pressure casting device comprising a mold ada ted to receive a frame in or about which a lliody is to be cast, a plurality "of reservoirs associated'with said mold, a plurality of communicating ports in said mold and reservoirs and pressure actuating means for discharging the reservoirs through said ports, said means com rising a plurality of Huid pressure actuate pistons. l

9. A pressure casting device comprising a mold, means for clamping ya body therein in such a manner as to provide a space which constitutes ythe matrix in which a casting is formed, a'reservoir for the top and the bottom of said mold having communicating ports therebetween and pressurel actuating means for discharging the said reservoirs successively.

In testimony whereof, I have hereunto vember, 1923. l JESSE L. JONES.

subscribed my name this 14th day of No- "0 

